1. Field of the Invention
The present invention relates to an atmosphere regulator and a method for culturing anaerobic bacteria. More specifically, it relates to an atmosphere regulator and an atmosphere regulator package which can regulate the concentration of a carbon dioxide gas, is excellent in oxygen absorption performance, does not bring about any deterioration of the performance even when stored for a long period of time, and is compact for putting into a package, and a method for culturing anaerobic bacteria by the use of this atmosphere regulator or this package.
2. Description of the Related Art
In recent years, it has been considered as a useful means for the inspection of bacteria that various anaerobic bacteria are cultured to detect their presence, and many techniques have been developed. In particular, it has been required to make an atmosphere suitable for the culture of the anaerobic bacteria in a simple manner, and various kinds of atmosphere regulators have been suggested. For example, as the atmosphere regulator for the culture of the anaerobic bacteria which contains an ascorbic acid compound, there has been disclosed an atmosphere regulator which can give an anaerobic state and a predetermined carbon dioxide gas concentration within 6 hours in Japanese Patent Application Laid-open Nos. 51890/1983 and 98686/1984. However, in order to regulate the atmosphere, a long time is taken, and so there is a problem that the accuracy of the bacteria inspection is impaired. In addition, Japanese Patent Application Laid-open No. 105288/1979 has disclosed a method for culturing anaerobic bacteria by the use of an atmosphere regulator mainly comprising an ascorbic acid compound and including two or more alkali compounds, but this method has a problem that the regulation of a pH is insufficient under the influence of a contained carbonate or hydrogencarbonate and a storage stability is poor.
Furthermore, in Japanese Patent Application Laid-open No. 202281/1989, there is disclosed an atmosphere regulator which comprises an ascorbic acid compound as a main component, an alkali hydroxide, an activated carbon, a ferrous salt, water and calcium silicate, but the mixture becomes unequal under the influence of the size of the alkali hydroxide to cause the scattering of a carbon dioxide gas concentration. In addition, an oxygen absorbing reaction is impaired by the influence of contained calcium silicate, so that the size of an package including the atmosphere regulator tends to increase.